How do I calculate the frequency of an observer

Tungsten-filament lightbulb emits light based on the temperature of the filament. which phenomenon does this demonstrate?

When applying kirchhoff's rules, one of the essential steps is to mark each resistor with plus and minus signs to label how the electric potential changes from one end of the resistor to the other. the circuit in the drawing contains four resistors, each marked with the associated plus and minus signs. however, one resistor is marked incorrectly. which one is it?

What part of the ear is names after tools, such as the hammer and the anvil?